JPH0475263B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a toner for developing electrostatic latent images in electrophotography, electrostatic recording, and the like. In electrophotography, a latent image is formed on a photoconductor made of a photoconductive substance, which is developed with a powder developer to become a visible image, and then transferred onto paper using heat, solvent, or in some cases pressure. The most common method is to establish The developer used in such electrophotography is a mixture of fine particle powder made of resin and colorant called developer powder or toner, and microscopic glass beads called carrier, iron powder, or iron powder whose surface has been treated with various resins. Ru. In this case, a developer using extremely fine ferrite or magnetite as a carrier is called a one-component developer, and can be distinguished from the former. The present invention relates to developer powder called toner of these developers. The photoconductor layer can be positively or negatively charged so that exposure under the original produces a positive or negative electrostatic latent image. Therefore, a positively charged positive image is generated on the negative electrostatic latent image. However, when a positively electrostatic latent image is developed with negatively charged developer powder, the black and white tones are reversed and a negative image of the original, that is, a positive negative image is obtained. As described above, there are two types of developer powder for electrophotography: positively charged developer powder and negatively charged developer powder. The present invention relates to negatively charged developer powder. Generally, developer powder is a fine powder made by mixing synthetic resin with coloring agents such as dyes and pigments. In order to charge the developing powder negatively, the dye mixed therein plays an important role not only in coloring but also in its electrostatic properties as a charge control agent. In particular, most of the dyes and pigments conventionally used as coloring agents are positively charged, and if they are negatively charged, their charging properties are weak, resulting in mixed mirror images or fog, making it difficult to obtain clear images. was not obtained. The present inventors focused on this point and developed a metal complex compound that has negative characteristics and particularly has extremely good compatibility with the resin used. As a result, it was possible to produce a developing powder with excellent electrostatic properties that improved all the drawbacks of conventionally used colorants. That is, the invention is based on the following formula: [In the formula, X ₁ and X ₂ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group, or a halogen atom; X ₁ and X ₂ may be the same or different; ' represents an integer of 1 to 3, R ₁ and R ₃ are hydrogen atoms, C ₁ to ₁₈ alkyl, alkenyl, sulfonamide, mesyl, sulfonic acid, carboxy ester, hydroxy, C ₁
~ ₁₈ alkoxy, acetylamino, benzoylamino groups or halogen atoms, R ₁ and R ₃
may be the same or different, n and
n' represents an integer from 1 to 3, R ₂ and R ₄ represent a hydrogen atom or a nitro group, and A represents a hydrogen ion, sodium ion, potassium ion, or ammonium ion. ] This is an electrophotographic developing powder containing a metal complex salt compound represented by the following as a charge control agent and a colorant. The above-mentioned metal complex salt compound has the property of being electrostatically negatively charged, and therefore, by mixing it with a suitable developing resin in a desired ratio, a negatively charged developing powder can be obtained very easily. Furthermore, there are many metal complex compounds as toner colorants similar to the compound represented by Formula 1 above, as detailed below, but the compound according to the present invention has a higher resistance to developing powder resin than known compounds. Compatibility is particularly good. Therefore, the developer powder is uniformly distributed in each of the fine particles. This is an important point regarding the charging characteristics of the developing powder. Furthermore, the dye of the present invention itself has an extremely large amount of negative charge. Regarding electrophotographic toners containing metal complex compounds, for example,
43-17955 and Japanese Patent Publication No. 43-27596, etc., the toner containing the metal complex compound represented by the general formula 1 of the present invention has a lower chargeability than those described in these publications. It has excellent properties and also shows negative results in the mutagenicity test (Ames test), making it suitable as an electrophotographic toner. On the other hand, the inventors have already developed an electrophotographic toner containing a metal complex compound as a similar compound.
Nos. 57-141452 and 58-11049, but compared to those inventions, the present invention is an iron complex compound. It is also extremely advantageous in terms of safety. Furthermore, it has extremely good compatibility or solubility with various resins that are the main binder components of toners, so when used as an additive in electrophotographic toners, it improves the charging stability of toners during continuous copying. The coloring power was excellent and the coloring power was high, so the copied images were extremely clear and it was possible to obtain copies with excellent gradation. The metal complex salt compound according to the present invention was first disclosed in JP-A-58
-The following formula according to the description in Publication No. 111049 [In the formula, X ₁ , X ₂ , n, m and A are as defined in the above formula 1. ] The metal complex salt compound represented by can be easily synthesized. In addition to the metal complex compound, the toner of the present invention also contains:
The toner of the present invention contains a binding substance and a coloring substance, and examples of binding substances that can be suitably used in the toner of the present invention include monomers of styrene and its substituted products such as polystyrene and polyvinyltriene, styrene-substituted styrene copolymers, Styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-acrylonitrile copolymer,
Polyvinyl chloride, polyethylene, silicone resin, polyester, polyurethane, polyamide,
Epoxy resins, modified rosins, phenolic resins, etc. can be used alone or in combination. Examples of coloring substances include CI Pigment Yellow 12, CI Solvent Yellow 16, CI Daybirds Yellow 33, CI Pigment Red 122,
CI Solvent Red 19, CI Pigment Blue
15, CI pigment black 1, CI solvent black 3, CI solvent black 22, carbon black, etc. can be used. Another feature of the present invention is that by using it in combination with a colored dye that has the effect of a conventionally known charge control agent, the drawback of lack of long-term stability of known charge control agents can be significantly improved. Hereinafter, the present invention will be explained in detail with reference to Examples, where parts are parts by weight. Example 1 14.4 parts of 4-chloro-2-aminophenol
After mixing with 26 parts of concentrated hydrochloric acid and 400 parts of water,
The mixture was cooled on ice to 0 to 5°C, 6.9 parts of sodium sulfite was added, and the mixture was stirred at the same temperature for 2 hours to diazotize. This diazotide was mixed with 300 parts of water, 10 parts of sodium hydroxide and 29.3 parts of 3-hydroxy-2 at 0 to 5°C.
After injecting into a mixture of -naphtho-0-anisidide and carrying out a coupling reaction, a monoazo compound having the following structural formula was isolated. This monoazo compound paste was dissolved in 120 parts of ethylene glycol, 5 parts of sodium hydroxide and 8.5 parts of ferric chloride were added, and the mixture was heated to 110-120°C.
After metallization by stirring for 3 hours, the mixture was cooled to room temperature, and the precipitated product was filtered and dried under reduced pressure at 50 to 60°C to obtain 45 parts of an iron complex compound as a blackish brown fine powder shown below. When this iron complex compound was dissolved in dimethylformamide, it exhibited a dark brown color (maximum absorption wavelength 450 nm). Production of toner: 100 parts of styrene-acrylic copolymer resin, 7 parts of carbon black, and the above-synthesized iron complex compound.
1.2 parts were added, mixed well, heated and melted, cooled and ground in a ball mill to obtain a fine, negatively charged developing powder. Next, a positive electrostatic latent image is formed on a selenium photosensitive plate charged by corona discharge (+5000V), and this positive image is transferred to paper and heat-fixed to create a clear halftone image without fogging. Clear images can be obtained, and continuous copying (running)9
Even after the 10,000th copy, there was almost no change in the development characteristics of the toner, and a good copy that was the same as the initial image was obtained. In addition, the amount of charge on the toner was measured using the blow-off method, and the initial charge
The charge amount of the toner at the 100,000th sheet of running is -22.5μc/g, which is almost the same as the initial value, and the charge distribution is -22.4 ~
-23.2 μc/g, which was almost uniform, and all were extremely excellent as toners. Examples 2 to 15 Metal complex salt compounds were synthesized according to Example 1, and toners were obtained by the same operation as Example 1 with the developer composition shown in the following table. The image properties and charging characteristics of these toners were also evaluated. They are summarized in the table.

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[Table] Example 16 Synthesis of metal complex compound; Dissolve the paste of the monoazo compound synthesized in Example 1 in 150 parts of ethylene glycol, then add 10 parts of concentrated sulfuric acid and 40 parts of ferric sulfate,
After stirring at 100°C for 3 hours to form a complex salt, a paste of the following monoazo compound synthesized on a 0.1 molar scale according to Example 1 was added. 12 parts of sodium hydroxide and 11 parts of sodium acetate were added and stirred at 95-100°C for 2 hours to produce an asymmetric 1:2 type iron complex salt compound, and the precipitated product was filtered at room temperature to form an isolated wet cake. is 50~
The mixture was dried at 60° C. under reduced pressure to obtain 95 parts of a fine black powder of an iron complex salt compound represented by the following formula. When this iron complex compound was dissolved in dimethylformamide, it exhibited a black color (maximum absorption wavelength 445 nm). Manufacture of toner: This iron complex salt compound was treated in the same manner as in Example 1 to obtain a developer. Next, a positive electrostatic latent image is formed on a selenium photosensitive plate charged by corona discharge (+5000V), and this positive image is transferred to paper and heat-fixed to create a clear halftone image without fogging. Clear images can be obtained, and continuous copying (running)9
Even after the 10,000th copy, there was almost no change in the development characteristics of the toner, and a good copy that was the same as the initial image was obtained. In addition, when the toner charge amount was measured using the blow-off method, the initial charge was -21.3 μc/g, and the toner charge amount at the 100,000th sheet of running was -21.0 μc/g, which was almost the same as the initial value. Regarding the distribution −
It was almost uniform at 2.0 to -21.4 μc/g, and all were extremely excellent toners. By using the metal complex salt compound shown below instead of the iron complex salt compound of Example 16, an extremely excellent toner could be obtained in the same manner as in Example 16. Example 17 Example 18

Claims (1)

[Claims] 1. The following general formula [In the formula, X ₁ and X ₂ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group, or a halogen atom; X ₁ and X ₂ may be the same or different; ' represents an integer of 1 to 3, R ₁ and R ₃ are hydrogen atoms, C ₁ to ₁₈ alkyl, alkenyl, sulfonamide, mesyl, sulfonic acid, carboxy ester, hydroxy, C ₁
~ ₁₈ alkoxy, acetylamino, benzoylamino groups or halogen atoms, R ₁ and R ₃
may be the same or different, n and
n' represents an integer from 1 to 3, R ₂ and R ₄ represent a hydrogen atom or a nitro group, and A represents a hydrogen ion, sodium ion, potassium ion, or ammonium ion. ] An electrophotographic toner comprising a metal complex compound represented by: